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From mwiederk...@apache.org
Subject svn commit: r731132 - in /james/mime4j/trunk/examples/src/java/org/apache/james/mime4j/samples/transform: ./ TransformMessage.java
Date Sun, 04 Jan 2009 00:09:41 GMT
Author: mwiederkehr
Date: Sat Jan  3 16:09:40 2009
New Revision: 731132

URL: http://svn.apache.org/viewvc?rev=731132&view=rev
Log:
Added message transformation example

Added:
    james/mime4j/trunk/examples/src/java/org/apache/james/mime4j/samples/transform/
    james/mime4j/trunk/examples/src/java/org/apache/james/mime4j/samples/transform/TransformMessage.java

Added: james/mime4j/trunk/examples/src/java/org/apache/james/mime4j/samples/transform/TransformMessage.java
URL: http://svn.apache.org/viewvc/james/mime4j/trunk/examples/src/java/org/apache/james/mime4j/samples/transform/TransformMessage.java?rev=731132&view=auto
==============================================================================
--- james/mime4j/trunk/examples/src/java/org/apache/james/mime4j/samples/transform/TransformMessage.java
(added)
+++ james/mime4j/trunk/examples/src/java/org/apache/james/mime4j/samples/transform/TransformMessage.java
Sat Jan  3 16:09:40 2009
@@ -0,0 +1,171 @@
+package org.apache.james.mime4j.samples.transform;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.util.Random;
+
+import org.apache.james.mime4j.field.Field;
+import org.apache.james.mime4j.message.Body;
+import org.apache.james.mime4j.message.BodyFactory;
+import org.apache.james.mime4j.message.BodyPart;
+import org.apache.james.mime4j.message.Header;
+import org.apache.james.mime4j.message.Message;
+import org.apache.james.mime4j.message.Mode;
+import org.apache.james.mime4j.message.Multipart;
+import org.apache.james.mime4j.message.storage.DefaultStorageProvider;
+import org.apache.james.mime4j.message.storage.StorageProvider;
+import org.apache.james.mime4j.message.storage.TempFileStorageProvider;
+import org.apache.james.mime4j.util.MimeUtil;
+
+/**
+ * This code should illustrate how to transform a message into another message
+ * without modifying the original.
+ */
+public class TransformMessage {
+
+    // Host name used in message identifiers.
+    private static final String HOSTNAME = "localhost";
+
+    public static void main(String[] args) throws Exception {
+        // Explicitly set a strategy for storing body parts. Usually not
+        // necessary; for most applications the default setting is appropriate.
+        StorageProvider storageProvider = new TempFileStorageProvider();
+        DefaultStorageProvider.setInstance(storageProvider);
+
+        // Create a template message. It would be possible to load a message
+        // from an input stream but for this example a message object is created
+        // from scratch for demonstration purposes.
+        Message template = createTemplate();
+
+        // Create a new message by transforming the template.
+        Message transformed = transform(template);
+
+        // Print transformed message.
+        System.out.println("\n\nTransformed message:\n--------------------\n");
+        transformed.writeTo(System.out, Mode.STRICT_ERROR);
+
+        // Messages should be disposed of when they are no longer needed.
+        // Disposing of a message also disposes of all child elements (e.g. body
+        // parts) of the message.
+        transformed.dispose();
+
+        // Print original message to illustrate that it was not affected by the
+        // transformation.
+        System.out.println("\n\nOriginal template:\n------------------\n");
+        template.writeTo(System.out, Mode.STRICT_ERROR);
+
+        // Original message is no longer needed.
+        template.dispose();
+
+        // At this point all temporary files have been deleted because all
+        // messages and body parts have been disposed of properly.
+    }
+
+    /**
+     * Copies the given message and makes some arbitrary changes to the copy.
+     */
+    private static Message transform(Message original) throws IOException {
+        // Create a copy of the template. The copy can be modified without
+        // affecting the original.
+        Message message = new Message(original);
+
+        // In this example we know we have a multipart message. Use
+        // Message#isMultipart() if uncertain.
+        Multipart multipart = (Multipart) message.getBody();
+
+        // Insert a new text/plain body part after every body part of the
+        // template.
+        final int count = multipart.getCount();
+        for (int i = 0; i < count; i++) {
+            String text = "Text inserted after part " + (i + 1);
+            BodyPart bodyPart = createTextPart(text);
+            multipart.addBodyPart(bodyPart, 2 * i + 1);
+        }
+
+        // For no particular reason remove the second binary body part (now
+        // at index four).
+        BodyPart removed = multipart.removeBodyPart(4);
+
+        // The removed body part no longer has a parent entity it belongs to so
+        // it should be disposed of.
+        removed.dispose();
+
+        // Create a unique message ID for the new message.
+        Header header = message.getHeader();
+        Field messageId = Field.parse("Message-ID: "
+                + MimeUtil.createUniqueMessageId(HOSTNAME));
+        header.setField(messageId);
+
+        // Set a new subject; note the usage of setField instead of addField
+        header.setField(Field.parse("Subject: Transformed message"));
+
+        return message;
+    }
+
+    /**
+     * Creates a multipart/mixed message that consists of three parts (one text,
+     * two binary).
+     */
+    private static Message createTemplate() throws IOException {
+        Header header = new Header();
+        header.addField(Field
+                .parse("Content-Type: multipart/mixed;\r\n\tboundary=\""
+                        + MimeUtil.createUniqueBoundary() + "\""));
+        header.addField(Field.parse("Subject: Template message"));
+
+        Multipart multipart = new Multipart("mixed");
+
+        BodyPart part1 = createTextPart("This is the first part of the template..");
+        multipart.addBodyPart(part1);
+
+        BodyPart part2 = createRandomBinaryPart(200);
+        multipart.addBodyPart(part2);
+
+        BodyPart part3 = createRandomBinaryPart(300);
+        multipart.addBodyPart(part3);
+
+        Message message = new Message();
+        message.setHeader(header);
+        message.setBody(multipart);
+
+        return message;
+    }
+
+    /**
+     * Creates a text part from the specified string.
+     */
+    private static BodyPart createTextPart(String text) {
+        Header header = new Header();
+        header.addField(Field.parse("Content-Type: text/plain"));
+
+        Body body = new BodyFactory().textBody(text);
+
+        BodyPart bodyPart = new BodyPart();
+        bodyPart.setHeader(header);
+        bodyPart.setBody(body);
+
+        return bodyPart;
+    }
+
+    /**
+     * Creates a binary part with random content.
+     */
+    private static BodyPart createRandomBinaryPart(int numberOfBytes)
+            throws IOException {
+        Header header = new Header();
+        header.addField(Field.parse("Content-Type: application/octet-stream"));
+        header.addField(Field.parse("Content-Transfer-Encoding: base64"));
+
+        byte[] data = new byte[numberOfBytes];
+        new Random().nextBytes(data);
+        Body body = new BodyFactory()
+                .binaryBody(new ByteArrayInputStream(data));
+
+        BodyPart bodyPart = new BodyPart();
+        bodyPart.setHeader(header);
+        bodyPart.setBody(body);
+
+        return bodyPart;
+    }
+
+}



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